[Stoves] Jatropha fruit as fuel? A humorous analogy
Jonathan Otto
ottojonathan at hotmail.com
Mon Jan 21 17:03:53 CST 2013
Stovers,
Paul was correct: I meant incomplete combustion.
Meanwhile I shared some of the voluminous recent posting on Jatropha seed and pelletized fuel of Jatropha seedcake with a few Jet City StoveWorks colleagues not on the list.
One of them came up with the following commentary, which I share with you by permission of the author. May we all keep our sense of humor in these exchanges!
Jonathan
On the subject of Jatropha as a fuel:
A simple analogy (or folk tale) to view the Whole Seed vs Briquette Fuel discussion:
Let us say you have a great abundance of resinous pine cones in your region and the villagers don't even pick them up. It is discovered that the dried cones, with no processing, burn hot and clean in a specially designed TLUD cookstove. (It takes some experimenting to get the best balance of primary/ secondary air supply but Paul Anderson gives you some pointers) Then you have your stove tested at both Aprovecho Research Center and at the CREEC lab in Uganda: the results are encouraging.
Word gets out about the Whole-Cone stove and the way it uses the resin in the pine cones for fuel.
Some other stovers are encouraging and want to hear more.
But there is also a dedicated pelletizer-briquittezer school that claims there is a more advanced way to utilize pine cones as fuel. They claim it is far better to:
[1] have villagers collect the pine cones, then
[2] transport the cones to a town where electricity is available, then
[3] run them through an expeller machine that removes most of the resin, then
[4] take the pine cone remains and run it through a machine that mashes up the pine cone cake and shapes them into uniform sized bits of fuel, then
[5] truck the pellets back to the villagers for them to buy and then burn in an Improved Cook Stove, which is designed to optimize this newly made fuel: the Pine-Pellet stove,finally
[6] sell the extracted pine resin for European industrial use
(We will assume for the tale that the new Pine-Pellet Stove is tested for efficiency and emissions and scores satisfactorily same as the Whole-Cone stove)
So which one do you imagine is better? Lots of factors:
> Which one is better for the environment (ie. carbon footprint)?
> Better for the resin buyers?
> Better for the Chinese expeller makers?
> Which system will likely have the fewest mechanical problems over time?
> Which is better if (when) the price of truck fuel rises? Or the roads are impassible?
> When the electricity for the expeller machine goes out?
> When the machines and trucks need replacing?
> Finally which is better for the villagers? Collecting the cones and using them directly?
Or having the pellet fuel system?
The discussion continues......
David P Otto
Consultant to Jet City StoveWorks
Date: Sun, 20 Jan 2013 15:25:04 -0600
From: psanders at ilstu.edu
To: stoves at lists.bioenergylists.org
CC: ottojonathan at hotmail.com; dcovert at u.washington.edu; nathan at grotontimberworks.com; davidpotto at gmail.com; wastemin1 at verizon.net; solarbobky at yahoo.com
Subject: Re: [Stoves] Jatropha fruit as fuel? -- and possible project
Jonathan,
You wrote:
we too have had the experience of getting smoke and incomplete gasification from very dry seed that was stored too long in arid conditions.
I suspect you meant to say "incomplete combustion of the gases". I suspect that your very dry fuel did get pyrolyzed all the way to charcoal. (and I suspect that you are not referring to the gasification of the char, which should not be allowed to occur inside of TLUD stoves because the high heat of char-gasification is detrimental to the metal of the stoves.).
There seem to be enough Jatropha seeds for both pressing them for oil AND for using some directly as seed-fuels. Advantages of seed fuels include:
1. Already packaged with a natural protective coating (seed coat, not referring to the outer husk/shell)
a. to prevent entry of water (until conditions exist for sprouting). Moisture content (MC) is reasonably consistent in intact seeds if you give them a little protection from the rain.
b. clean to the touch when handling the fuel. They scoop well, and make no dust.
c. giving curved sides that allow passage of the needed Up-Draft primary air in TLUDs
d. (minor negative) prevent quick ignition, so we solve that by breaking up a few seeds to be at the top for ignition. But no need to crack them all.
2. Packed with energy in the form of carbohydrates (and other "stuff" like oils that burn).
a. That is why we do not burn most seeds, because they have value as food.
b. But Jatropha seeds are inedible, so we can burn them.
c. The oils can be vaporized by the heat, meaning the pyrolysis does not occur for the oils.
d. Therefore, per unit of energy ultimately in the combustion flame, there is LESS charcoal produced per unit of weight than is the case of wood and maize cobs, etc.
3. And specifically Jatropha seeds are about the right size for collection, storage, handling, air passage. And do not forget that the outer husk/hull can also be collected and used as fuel.
4. About the press-cake after oil extraction. What I have seen (Mozambique and Uganda) does not appeal much to me as a fuel. It needs further handling, is oily, and oil that does not dry remains slippery and therefore is not naturally great for making pellets or briquettes stick together. IF the press cake is being produced, then certainly consider using it as a fuel. But do not expect it to be easy or clean or even cheap. Certainly not as inexpensive as the intact seeds.
Again, I will sing the praises of Jet City Stoveworks (Otto brothers Jon and David and Prof. David Covert) and of Nathan Puffer (Vermont, not NH) for their work with whole Jatropha seeds in TLUD-ND (Jiko Safi) and TLUD-FA stoves, respectively. And also Hugh McLaughlin who has done experimental work with oil seeds as fuels in TLUDS (used sunflower seeds as a substitute).
We hope to see the Jiko Safi at ETHOS next week. Maybe there will be sufficient interest and attendance that we can build with and upon the Safi work.
Paul
Paul S. Anderson, PhD aka "Dr TLUD"
Email: psanders at ilstu.edu Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.comOn 1/20/2013 12:16 PM, Jonathan Otto wrote:
Alex,
You and Ron Larson have the memory of an elephant. Yes, I did make early postings to this list seeking help as we tried to develop a stove to burn liquid Jatropha oil many years ago. As our German colleagues at Siemens demonstrated over sevearl years of interesting failures, a cheap, easy-to-maintain stove fueled by plant oils is very difficult or maybe impossible. Then, for our efforts in Tanzania, Paul Anderson came along, preaching the gospel of TLUD, and we realized that extracting J oil as a liquid fuel was both unnecessary and inappropriate, when we can gasify these oils from within the seed.
Moisture level. We've not done any systematic testing of seed moisture levels, but it's rarely an issue since people only harvest J seeds when they're completely dry on the vine. Some sun drying helps if they get wet. Going back to a comment Dean made recently about fuel being too dry to gasify well, we too have had the experience of getting smoke and incomplete gasification from very dry seed that was stored too long in arid conditions. We need more field experience to say anything more useful about this.
Carl Beilenberg and J oil for electrical generation. I have fallen out of touch with Carl in recent years, so I don't know what my fellow Vermonter is up to these days, but you can bet it's highly inventive. I do know that he used to run his diesel VW on J oil -- quite a trick for such a viscous fuel in our northern climate. Since J seed is still not a traded commodity in most places, the economics of using it as fuel -- solid or liquid -- can't be definitively determined, or I should say, will be highly site-specific. The on-farm price range for J seed, excepting ridiculous spikes that occurred during the Jatropha silly period of the biofuel bubble after 2005, runs from around US$0.12 to $0.25 per-kilo in my experience. Depending on efficiency of extraction methods, quality of seed, etc., one can get 1 liter from 3.5 kg - 5 kg of seed. Of course, feedstock is only one part of the cost equation.
Thanks for yoiur interest,
Jonathan
Date: Sun, 20 Jan 2013 10:14:42 -0500
From: english at kingston.net
To: stoves at lists.bioenergylists.org
Subject: Re: [Stoves] Jatropha fruit as fuel?
Hi Jonathan,
Its good to hear about the progress you have made. I can remember your early missives to this list, was it a decade ago?
A few questions... about the stove;
At what moisture level (in the whole seed) do you see a drop off in emissions performance when burned in the Jiko Safi?
Is it easy for the users to tell when the seeds are dry enough?
...about biofuel;
Part of the idea was to provide electricity or shaft power to communities or business with a Lister engine on Jatropha oil.
I remember visiting Carl Bielenberg's workshop where he was doing the testing.
Any success stories there or is diesel always cheaper without a carbon consideration?
Alex
On 20/01/2013 9:23 AM, Jonathan Otto wrote:
Hey Richard,
Not sure why you feel my briquetting education has been neglected, since that kind of fuel is not mentioned in any of my postings; but I certainly subscribe to Dean's comment: we all have a lot to learn about such alternative fuels. I would add: and the stoves that burn them in a truly clean way. Which brings up the question: if a briquette or pellet is burned in an open charcoal brazier, do we have a clean energy source? To put in another way, there are no 'clean' or 'dirty' fuels; it's combination of fuel and stove that must be evaluated together for emissions and other performance parameters.
My densified fuels question to Otto the Senior or anyone else who can enlighten me concerning the logic of pelletizing Jatropha presscake. If farmers grow their own energy-dense, uniform-sized fuel, i.e., whole Jatropha seed, why complicate matters by processing that ready-to-use fuel into another fuel? No matter how efficient the pelletizing process, it must require time and energy. Why not burn these seeds directly in a micro gasifier stove, such as our jiko safi?
Let me try to head off some likely comments. I know that there are companies in many African and Asian countries engaged in commercial scale production of Jatropha (and other biofuel crops) for export of biodeisel. Land grabbing and other nefarious activities of some of these players are obscene, as once again the global north exploits tropical countries for cheap/free land and cheap labor to meet its own needs.
Yes, those Jatropha oil export ventures produce presscake as a by-product which they pelletize and market for fuel. And yes, some smaller operations in a few countries like Uganda, are trying to make a go of producing Jatropha-based biofuels for local and regional energy markets. But for all the publicity, most of it appropriately negative, in the 'food vs. fuel' analysis, there's a lot more to Jatropha than current attempts to put the oil in European cars and jet engines.
Far apart from all these recent commercial Jatropha ventures, many of which are unprofitable for reasons we can discuss another time if anyone's interested, are many millions of farmers in over 110 countries who use Jatropha as a living hedge and for medicianl uses. Seems it's grown in every frost-free area of the world. I've found it from Cuba -- it's native to the neo-tropics -- to Mali, which has thousands of kilometers of hedges, to Bhutan where villagers were obliged to pay a Jatropha tax to monks for lighting in floating wick lamps.
My guess is that over 99% of all Jatropha seed fall to the ground and rot, unused. (One study in a district of Tanzania where Jatropha seed is a traded commodity found that only 6% of seed is harvested.) As we all search for renewable, sustainably harvested biomass to fuel our favorite stoves, can we afford to overlook seeds of this ubiquitous, multi-use species?
The point of importuning my stove list colleagues on a fine Sunday morning is to interest other stove makers to look at Jatropha and other energy-rich seeds as a category of fuel worth consideration for new stove designs. We are modestly pleased with the performance of the jiko safi, but we also know that some of you with far deeper understanding of gasification and far more experience in stove design could produce a much better model. Anyone want to take up this challenge?
Over to you,
Jonathan
From: rstanley at legacyfound.org
Date: Sat, 19 Jan 2013 20:46:53 -0600
To: stoves at lists.bioenergylists.org
Subject: Re: [Stoves] Jatropha fruit as fuel?
Dear Ottos,
Seems you both need training in briquettemaking . Jon you know where to go in nchi yeti but Otto, where are you based? Seriously, the blends you are finding smelly smokey etc suggests that you get in touch with any of hundreds of others who can train you.
Richard Stanley
Monte Rico,
Guatemala
Sent from my iPhone
On Jan 19, 2013, at 18:10, Otto Formo <terra-matricula at hotmail.com> wrote:
Josh and Jonathan (Otto),
Yes, we are talking about the presscake of Jatropha and it was processed into pellets localy in Zambia, quite easily and with "simple" tools - (no waste of energy)
We had the same experience as your colleagues using briquettes made out of ricehusks and sawdust.
They even started to glow like charcoal early in the gasification process and produced smoky and smouldery combustion.
Thast why we prefer to use pellets of best possible quality.
I hope you are correct about the gasification of jatropha pellets will destroy the phorbol esters and other problematic compounds instead of emitting them.
Iam a bit worried about the forced draft units, while they seems to blow some parts of the ash and gases into the open air or room.
May be the char from Jatropha could have a pestecide effect as well?
Otto
Date: Sat, 19 Jan 2013 18:23:35 -0500
From: yeah.yeah.right.on at gmail.com
To: stoves at lists.bioenergylists.org
Subject: Re: [Stoves] Jatropha fruit as fuel?
Otto - FYI jatropha presscake (the mealy material left over once oil has been pressed out of the seeds) can be directly pelletized without further processing. It's pretty easy to pelletize, even with a small, cheaper (e.g. benchtop) pellet press. The mealy presscake still contains some of the oil (think coffee grounds) and it pelletizes well without worry over moisture content or having to use a binder.
The pellets burn in a TLUD similar to wood or other pellets, at least by visual observation and temperature recording. I have colleagues that have tried to make cooking briquettes with jatropha seedcake and had a very smoky, smouldery combustion. I believe there are concerns of some potentially toxic emissions (phorbol esters, other compounds?). I have not tested the emissions from TLUD charring jatropha pellets, but there was no visible smoke and the gasifier seemed to operate fine as it does with other types of pellets. It would be interesting to know if firing jatropha pellets in a TLUD destroys the phorbol esters and other problematic compounds instead of emitting them.
I first tried to char un-pelletized jatropha seedcake in the TLUD - because it is mealy like coffee grounds no draft could get through and it was a total fail - lots of smoke poured out! This brought the fire department to our Colorado backyard during a fire ban. Whoops.
Also FYI char made from TLUD jatropha pellets performed similar for herbicide uptake from simulated natural water as chars made in the same way from pine pellets, bagasse pellets, and bamboo pieces.
Josh
On Sat, Jan 19, 2013 at 12:29 PM, Jonathan Otto <ottojonathan at hotmail.com> wrote:
Otto,
Whole Jatropha seeds can be picked from hedges on-farm and used directly in our jiko safi gasification stove without any further effort (except maybe for some sun drying if harvested during a damp season) … the most decentralized, efficient sustainable fuel system I can imagine.
Sure, urban jiko safi users will need to buy their fuel seeds, so a commercial system for transport and retail sale of seed will be needed eventually, likely mimicking some aspects of the charcoal trade. But it’s just whole, unprocessed seed.
Concerning pelletized Jatropha fuel, I would like to understand the advantages you find in going through the costs and effort (including energy losses) of processing seeds to expel the oil, then probably milling the press cake and shells (?) to uniform size/texture, then extruding or otherwise forming the mixture into pellets, and finally distribute the fuel, some of which will go back to the same farmers that grew the Jatropha seed in the first place?
I know there are technical advantages to gasification of uniform-sized pellets, but it seems to me that round or ovoid shaped seeds like Jatropha, castor (I know, more poisons!), shea or croton megalocarpus provide this same advantage, without going through the pelletization process. What am I missing?
Otto, the minor
P.S. It's too late for me to retire 'on time'
From: terra-matricula at hotmail.com
To: stoves at lists.bioenergylists.org
Date: Sat, 19 Jan 2013 17:23:37 +0100
Subject: Re: [Stoves] Jatropha fruit as fuel?
Jonathan,
We have got some samples of pelletized jatropha shells and seeds from Zambia, after the oil has been extracted and we feel that is the way forward.
We will update you on the progress, so you will be albe to retire "on time".................:)
We are not so worried about PM in natural draft gasifiers, but thanks for the concern.
Otto........................
From: ottojonathan at hotmail.com
To: stoves at lists.bioenergylists.org
Date: Sat, 19 Jan 2013 09:03:35 -0500
Subject: Re: [Stoves] Jatropha fruit as fuel?
Otto-
You 'would guess' wrong.
'We should be very careful advising people' about such unsupported conclusions.
The challenges of gasifying oils found in seeds, notably the oils of Jatropha seed, in a cookstove are far different from working with most pellets formulations.
I keenly look forward to news of your all-fuel stoves that will handle J seeds, and the results of your tests. I sincerely hope you develop this soon, so I can finally retire in peace.
Oh, and when you do tests, please include particulates in your emissions testing, so we can finally end all this hand wringing about 'these types of fuel'.
>From the cheeky other Otto,
Jonathan
From: terra-matricula at hotmail.com
To: stoves at lists.bioenergylists.org
Date: Fri, 18 Jan 2013 23:23:48 +0100
Subject: Re: [Stoves] Jatropha fruit as fuel?
Dear stovers,
I would guess that "any" gasifier will burn jatropha seeds or pellets cleanly and efficient, as long as the moisture content are less than 10%.
We have in the pipeline to test a new design of natural draft gasifiers, using jatropha seeds and pellets, for emmissions and toxcic fumes.
We should be very carefull adviceing people using these types of fuel, before it has been carefully tested by independent institutions.
Have a nice weekend.
Otto (not the famous one..........:)
From: crispinpigott at gmail.com
To: stoves at lists.bioenergylists.org
Date: Fri, 18 Jan 2013 10:19:11 -0500
Subject: Re: [Stoves] Jatropha fruit as fuel?
Dear Jonathan
I am interested in the general layout and dimensions of a stove that will burn the seeds well. Are you sharing at this time anything regarding the design?
Thanks
Crispin
++++++++
Dear Joyce and stovers all,
My regrets for not responding to this request 6 months ago. I admit that it got lost in my messy inbox which I have now reduced from 6000 messages to a mere 2400, and in the process uncovered Joyce's email.
Burning Jatropha seeds whole or in briquettes in open cooking arrangements is a bad idea. It produces a smoky, smelly fire and probably exposes cooks to toxic emissions. I even question burning Jatropha oil in lamps in enclosed areas for the same reason. Maybe others know of emissions studies.
[snip]
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://www.bioenergylists.org/
--
Josh Kearns
PhD Candidate, Environmental Engineering
University of Colorado-Boulder
Visiting Researcher, North Carolina State University
Director of Science
Aqueous Solutions
www.aqsolutions.org
Mobile: 720 989 3959 begin_of_the_skype_highlighting 720 989 3959 end_of_the_skype_highlighting
Skype: joshkearns
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://www.bioenergylists.org/
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://www.bioenergylists.org/
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://www.bioenergylists.org/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20130121/988015e3/attachment.html>
More information about the Stoves
mailing list